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Purpose: The objective of this study was to investigate the relationship between various clinical factors and bacterial contamination of bone chips (BC) collected during dental implant surgery and to elucidate how bacterial contamination might be minimized. Materials and Methods: Implants were installed in 55 partially edentulous patients (36 men and 19 women), among whom the relationship between various clinical factors and bacterial contamination of BC collected by bone trap was investigated in 37. The effect of rinsing with a saline on BC was determined in 18 patients. Number of contaminating microorganisms was expressed as colonyforming units (CFUs). Results: CFUs in the maxilla were lower than those in the mandible (P < 0.01). CFUs at the incisors or canines were lower than those at the premolars or molars (P < 0.01). Logistic regression analysis revealed a relationship between average bacterial count and duration of surgery (odds ratio, 1.046; 95% CI, 1.012- 1.081). Rinsing of BC reduced bacterial contamination. Conclusion: Duration of surgery is a major clinical factor affecting contamination risk in BC, and rinsing of BC with a sterile saline solution reduces bacterial number. [ABSTRACT FROM AUTHOR]

Objectives: Actinobacillus actinomycetemcomitans is a major causative agent of chronic and aggressive periodontitis. Freshly isolated strains of A. actinomycetemcomitans display rough-type colonies and initiate biofilm formation on glass surfaces. The purpose of this study was to determine the antibiotic susceptibility of A. actinomycetemcomitans biofilm during different phases of maturation.Methods: Using 96-well microtitre plates, we determined the antibiotic susceptibility of rough-type strain 310a to concentrations from 0.1 to 10 mg/L each of erythromycin, ofloxacin, ampicillin, cefalexin, tetracycline and minocycline during biofilm formation. Antibiotics were added at the start of the culture (early phase) and after 24 h of cultivation (mature phase).Results: Adding 10 mg/L of ampicillin, 10 mg/L of cefalexin, 0.1 or 1 mg/L of tetracycline, or 0.1 mg/L of minocycline significantly inhibited 310a biofilm formation in the early phase, but not in the mature phase. Although adding 10 mg/L of erythromycin, tetracycline or minocycline reduced biofilm development in the early phase, it enhanced 310a biofilm development in the mature phase. Ofloxacin exerted a strong inhibitory effect in both the early and mature phases of biofilm formation throughout all experiments.Conclusions: The present study demonstrated that the susceptibility of A. actinomycetemcomitans to many antibiotics decreased after biofilm maturation. [ABSTRACT FROM AUTHOR]